[#291] Repl in morley sh

Description

Problem: morley repl can be easily used inside docker container but with one limitation about stack dump files, they can be used inside docker container but cannot be extracted from it once the repl have finished its work.

Solution: Add --map-dir option that mounts directory on the host filesystem with directory / in container filesystem, thus files can be extracted from the stopped docker container. This leads to a limitation that snapshots that need to be saved should be in the /<dirname>.

Related issue(s)

Resolves #291 (closed)

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